Carbon nanotubes provide key to gas filters

Today's best molecular filters, siliceous zeolites, filter gases too slowly to be of much use for everyday applications. So researchers at Carnegie Mellon University in Pittsburgh, PA, have an alternative solution: carbon nanotubes. Using atomistic simulations, David Sholl and associates calculated both self- and transport diffusivities of light gases in carbon nanotubes and in two zeolites with comparable pore sizes. The carbon nanotube filter gases 100 to 1,000 times faster than siliceous zeolites or any microporous material for which experimental data are available. This increased speed implies that nanotubes could provide a practical way to make large-scale gas filters, says Sholl. For more information, e-mail David S. Sholl at sholl@andrew.cmu.edu.

Industrial workplaces are governed by OSHA rules, but this isn’t to say that rules are always followed. While injuries happen on production floors for a variety of reasons, of the top 10 OSHA rules that are most often ignored in industrial settings, two directly involve machine design: lockout/tagout procedures (LO/TO) and machine guarding.

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